Aircraft tuning (チューニング) is a gameplay feature that allows players to equip modification parts to their aircraft. These parts change an aircraft's capabilities in various ways, from its flight mechanics to its weapon performance.
Tuning was first introduced in Ace Combat X: Skies of Deception, where players can equip one part to five categories but only on most fictional aircraft. This system returned and expanded to all aircraft in Ace Combat: Joint Assault and Ace Combat: Assault Horizon Legacy.
Ace Combat Infinity was the first console Ace Combat game to feature tuning. Unlike the handheld games, Infinity had three aircraft tuning categories with a certain number of slots per category. Players could equip a maximum of seven parts within the slot restrictions. Ace Combat 7: Skies Unknown followed this format and expanded the maximum to eight parts.
Aircraft parts in Ace Combat Infinity and Ace Combat 7 are divided into three categories: Body, Arms, and Misc (miscellaneous). Body parts affect the aircraft's performance, including speed, mobility, defense, and stealth. Arms parts affect the aircraft's machine gun, standard missiles, and offensive special weapons. Misc parts affect other aspects of the aircraft not covered by Body or Arms, including defensive special weapons. The player unlocks and purchases parts using the Aircraft Tree.
All aircraft can only carry a maximum of seven (Ace Combat Infinity) or eight (Ace Combat 7) parts in total. Each aircraft has a limited number of 'slots' for each category, and every part consumes slots in its category when equipped, based on its performance. For example, in Ace Combat 7, installing a Variable Cycle Engine Lv. 1 on an F-15C Eagle will use six of its 36 body slots, which can be freed up by uninstalling the part.
Tiers and levels
In Ace Combat Infinity, parts were duplicated in different tiers of effectiveness: Small (S), Lightweight (LW/SS, depending on region), Medium (M), Large (L), and Extra Large (LL). The higher the tier, the more effective the part but the more category slots it would consume. The only exception was Lightweight parts, which consumed less slots than Small despite being more effective. Only one tier of a part could be equipped at a time.
In Ace Combat 7, the tiers have been replaced by a leveling system but otherwise function exactly the same as they did in Infinity. Level 1 parts are available in both single-player and multiplayer, but level 2 and level 3 parts can only be used in multiplayer and can only be unlocked after playing at least one multiplayer match.
Exclusive to Ace Combat Infinity, players could upgrade the number of an aircraft's part slots. The simplest method was by leveling up the aircraft. All aircraft received two additional part slots for each category at level 6, one at level 15, and one at level 20.
Players could further expand an aircraft's part slots by repeatedly sortieing with it. After each online mission, the game granted Part Slot Expansion Points to the aircraft the player used, relative to the player's mission performance. The player could multiply these points if they used multiple Sortie Fuel at once (Forced Sortie). Once the plane's required amount of points for the next expansion was met, one additional part slot (marked in yellow) would be added to all three categories and any leftover points would count to the next expansion. Aircraft with a large number of part slots required exponentially more expansion points to the next expansion.
The maximum part slots per category was 38 at levels 1–5, 40 at levels 6–14, 41 at levels 15–19, and 42 at level 20. If an aircraft already had its maximum part slots, the part slot expansion points were converted into credits at a rate of 10 credits per point.
Aircraft parts in Ace Combat X, Joint Assault, and Assault Horizon Legacy are divided into five categories: Engine, Wing, Armor, Weapon, and Cockpit. Engine parts affect an aircraft's speed. Wing parts affect an aircraft's maneuverability. Armor parts affect an aircraft's defense. Weapon parts affect an aircraft's weaponry. Cockpit parts can affect any aspect of an aircraft. The player unlocks parts by completing missions or certain objectives and can purchase them in the hangar.
The player can only equip one part in each category on an aircraft. This system was restricted to most of the fictional aircraft in Ace Combat X: the XFA-24A Apalis, the XFA-27, the YR-302 Fregata, the XR-45 Cariburn, the YR-99 Forneus, the X-02 Wyvern, and the ADF-01 FALKEN. Despite it being a fictional aircraft, the Fenrir could not equip parts. This system was expanded in Joint Assault and Assault Horizon Legacy, allowing the player to equip parts to all aircraft, including the Fenrir in Joint Assault.